a small question about bpftool struct_ops

[Zhouyi Zhou]

Dear developers:
I compiled bpftool and bpf tests in mainline (2d1bcbc6cd70),
but when I invoke:
bpftool struct_ops register bpf_cubic.bpf.o

the command line fail with:
libbpf: struct_ops init_kern: struct tcp_congestion_ops data is not
found in struct bpf_struct_ops_tcp_congestion_ops
libbpf: failed to load object 'bpf_cubic.bpf.o'

The host OS I used to compile the kernel and bpf is Ubuntu 23.04, the
guest OS that I run bpftool is Ubuntu 22.04.
I have stumbled on this for several days, could you help me by guidance my way?

Thanks in advance
Zhouyi